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RELOG/src/model/solve.jl

110 lines
3.3 KiB

# RELOG: Reverse Logistics Optimization
# Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
# Released under the modified BSD license. See COPYING.md for more details.
using JuMP, LinearAlgebra, Geodesy, Cbc, Clp, ProgressBars, Printf, DataStructures
function _get_default_milp_optimizer()
return optimizer_with_attributes(Cbc.Optimizer, "logLevel" => 0)
end
function _get_default_lp_optimizer()
return optimizer_with_attributes(Clp.Optimizer, "LogLevel" => 0)
end
function _print_graph_stats(instance::Instance, graph::Graph)::Nothing
@info @sprintf("%12d time periods", instance.time)
@info @sprintf("%12d process nodes", length(graph.process_nodes))
@info @sprintf("%12d shipping nodes (plant)", length(graph.plant_shipping_nodes))
@info @sprintf(
"%12d shipping nodes (collection)",
length(graph.collection_shipping_nodes)
)
@info @sprintf("%12d arcs", length(graph.arcs))
return
end
function solve(
instance::Instance;
optimizer = nothing,
output = nothing,
marginal_costs = true,
return_model = false,
)
milp_optimizer = lp_optimizer = optimizer
if optimizer == nothing
milp_optimizer = _get_default_milp_optimizer()
lp_optimizer = _get_default_lp_optimizer()
end
@info "Building graph..."
graph = RELOG.build_graph(instance)
_print_graph_stats(instance, graph)
@info "Building optimization model..."
model = RELOG.build_model(instance, graph, milp_optimizer)
@info "Optimizing MILP..."
JuMP.optimize!(model)
if !has_values(model)
error("No solution available")
end
if marginal_costs
@info "Re-optimizing with integer variables fixed..."
all_vars = JuMP.all_variables(model)
vals = OrderedDict(var => JuMP.value(var) for var in all_vars)
JuMP.set_optimizer(model, lp_optimizer)
for var in all_vars
if JuMP.is_binary(var)
JuMP.unset_binary(var)
JuMP.fix(var, vals[var])
end
end
JuMP.optimize!(model)
end
@info "Extracting solution..."
solution = get_solution(model, marginal_costs = marginal_costs)
if output != nothing
write(solution, output)
end
if return_model
return solution, model
else
return solution
end
end
function solve(filename::AbstractString; heuristic = false, kwargs...)
@info "Reading $filename..."
instance = RELOG.parsefile(filename)
if heuristic && instance.time > 1
@info "Solving single-period version..."
compressed = _compress(instance)
csol = solve(compressed; output = nothing, marginal_costs = false, kwargs...)
@info "Filtering candidate locations..."
selected_pairs = []
for (plant_name, plant_dict) in csol["Plants"]
for (location_name, location_dict) in plant_dict
push!(selected_pairs, (plant_name, location_name))
end
end
filtered_plants = []
for p in instance.plants
if (p.plant_name, p.location_name) in selected_pairs
push!(filtered_plants, p)
end
end
instance.plants = filtered_plants
@info "Solving original version..."
end
sol = solve(instance; kwargs...)
return sol
end